Evolutionary cost-balancing arguments in welfare biology (the study of animal well-being in the wild) assume that producing suffering and happiness has metabolic or neural costs, and that natural selection allocated these states efficiently. A specific version of this reasoning – which I'll call the "Evening Out Argument" – holds that if a type of suffering is highly likely and largely unavoidable for an animal, evolution would reduce its intensity. The logic is that, if suffering functions to motivate learning and avoidance, then intense suffering provides little behavioral benefit when the animal can barely avoid the bad outcome anyway – it's just cost without payoff.

I argue this logic fails for large categories of animal experience. Most notably, it doesn't apply to background motivational states like hunger or anxiety, which function differently from discrete learning signals. I'll also discuss the prevalence of chronic and maladaptive suffering, concerns about the biological plausibility of some assumptions behind the Evening Out Argument, and why high infant mortality doesn't imply reduced suffering in long-lived species.

For context, many people familiar with the topic have explicitly stated that they do not consider cost-balancing arguments to be strong; however, I have seen some people [...]

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Outline:

(01:30) A brief history

(06:12) Mayflies vs baby turtles

(08:41) Hedonic accounting: discrete events vs background states

(13:14) Chronic suffering and old age

(15:27) Other biological plausibility concerns: path dependencies and modularity

(17:36) Ancestral environments and environmental mismatch

(19:11) Concluding thoughts and implications

(21:44) Appendix: A puzzle for Evening Out

(24:26) Acknowledgments

The original text contained 32 footnotes which were omitted from this narration.

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Narrated by TYPE III AUDIO.